线性表基本维护[ACM]

 #include "iostream"
 #include "string"
 using namespace std;

 typedef struct node{
     string data;
     struct node *next;
     node(string str){
         data=str;
         next=NULL;
     }

 }Node;

     Node *head=new node("hfirst");
     Node *back=new node("bfirst");
     Node *current=NULL;
     Node *pre=head;

 void add(string str){
     Node *temp;
     if(back->data=="bfirst")
         temp=new Node(str);
     else{
         temp=back->next;
         back->next=temp->next;
         temp->data=str;
         temp->next=NULL;
     }
     temp->next=head->next;
     head->next=temp;
     current=temp;
 }

 void move(int p){
     int i=;
     for(;i<p;i++){
         pre=current;
         if(current==NULL){
             cout<<"worng!!!"<<endl;
             current=head->next;
             pre=head;
             break;
         }
         else
             current=current->next;
     }

 }

 void del(int i){
     Node *temp=current;
     Node*tp;
     while(i!=&&current!=NULL){
         tp=current;
         current=current->next;
         i--;
     }
     if(current==NULL){

         back->next=pre->next;
         pre->next=NULL;
         pre=head;
         current=head->next;
     }
     else{
         pre->next=current;
         tp->next=NULL;
         temp->next=back->next;
         back->next=temp;
     }

 }
 void _print(){
     cout<<current->data;
 }

 void main(){
     string choice,str;
     int i;
     while(){
     cin>>choice;
         if (choice==("ADD")){cin>>str;add(str);}
         if (choice==("MOVE")){cin>>i;move(i);}
         if (choice==("DEL")){cin>>i;del(i);}
         if (choice==("PRINT"))_print();
     }
     getchar();
 }